Question

an iron pipe 20 cm long has external diameter 25 CM if the thickness of byte is 1 cm find the whole surface area of pipe​

Answer 1

Question. - An iron pipe 20cm long has external diameter 25cm nd if the thickness of the pipe is 1 cm .Then Find the Internal total surface area✓

Answer :-

Given length = 20cm

External diameter=25cm

Also given the thickness=1cm

So the internal diameter is( 25-1)cm

internal diameter = 24cm

So the internal T.S.A is as follows

$tsa = 2\pi \: r(r + h)...because \: the \: pipe \: is \: cylindrical$

$tsa = 2\pi \: 12(12 + 20).....( \: r = 12 \: becase \: r = \frac{diameter}{2} \\ \\ tsa = 24 \times 32\pi \\ \\ tsa = 768\pi$

Answer 2

Answer:

The surface area of the pipe is 3305.4 cm

Step-by-step explanation:

The circumference will be 78.7 cm

Then you multiply the circumference with 20cm-once for the external surface area and once for the internal surface area.

It will be 3148 cm.

Now the thickness is 1 cm on each side, so 78.7 cm is added to both sides, giving us the answer- 3305.4 cm